#include<stdio.h>

void run(void){
  int n,m;
  scanf("%d%d",&n,&m);
  int r=n%m;
  while(r>0){
    n=m;
    m=r;
    r=n%m;
  }
  printf("%d\n",m);
  return;
}

int main(void){
  run();
  return 0;
}